Total Mercury and Methylmercury Contamination of Fish from the Skalka Reservoir: A Case Study

Abstract

The aim of this case study was to investigate the total mercury and methylmercury contamination of fish from the Skalka reservoir, Czech Republic. The reservoir had been polluted with mercurycontaining sewage water for several decades. In total, 30 fish was sampled in August 2003. The fish caught included 5 roach (Rutilus rutilus), 8 bream (Abramis brama), 2 silver bream (Blicca bjoerkna), 7 big head carp (Aristichthys nobilis), 4 asp (Aspius aspius), 3 eel (Anguilla anguilla) and 1 wels catfish (Silurus glanis). Muscle tissue, the liver and the gonads were used for mercury determination. Total mercury in muscle tissue of the asp (as the representative of predatory species) and the bream (as the representative of non-predatory species) averaged 3.11 0.20 mgkg -1 and 0.96 0.22 mgkg -1 , respectively. All total mercury in muscle tissue of the asp and the bream was in methylmercury form. The content of total mercury and methylmercury was significantly (p < 0.05) higher in muscle tissue and the liver than in the gonads. The methylmercury-to-total mercury ratio in muscle tissue, the liver and the gonads averaged 1.012, 0.545 and 0.907, respectively. The results showed that mercury contamination of the Skalka reservoir continues to be very high, that consumption of predatory fish in particular poses a major health risk and that methylmercury was the predominant contaminant in fish tissues.